Generic air jet spinning machines are known from prior art. In the course of the spinning process, yarn faults occur repeatedly, that is, yarn sections form whose parameters (for instance yarn thickness, hairiness, yarn strength and so on) deviate from a given value. Yarn faults of this type are detected by a yarn sensor and must be removed in a clearer cut process which interrupts the spinning process. Yarn breaks (that is, the detaching of the yarn) are also a frequent occurrence, which also require the piecing of a yarn end to the fibre strand presented from the feed stock (so-called “piecing”). Bobbin changes are also necessary at regular intervals, in which a full bobbin, onto which the yarn is wound during the spinning process, is replaced by an empty bobbin.
In all cases, it is standard to release the respective wound-on yarn end from the bobbin surface with the aid of service robots patrolling the spinning stations, in order to be able to feed it in the opposite spinning direction to the spinning station again and to join it with the provided fibre strand. Furthermore, a certain section of the yarn must, as a rule, be removed before the piecing process takes place as the yarn end provided is mostly unsuitable for the spinning process.
Since service robots must first be moved to the respective spinning station and only one spinning station can be serviced by a robot, significant limitations in the spinning process occur due to the necessary piecing procedures. As a result, in particular the piecing processes, carried out in large numbers subsequent to the clearer cuts, contribute to a significant limitation in air jet spinning machine productivity.